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Rasmussen LJH, Caspi A, Ambler A, et al. Association of Neurocognitive and Physical Function With Gait Speed in Midlife. JAMA Netw Open. 2019;2(10):e1913123. doi:10.1001/jamanetworkopen.2019.13123
Is gait speed measured at age 45 years associated with accelerated biological aging, neurocognitive function, and cognitive decline?
In this 5-decade cohort study of 904 participants in New Zealand, physical and biological indicators of accelerated aging, including compromised brain integrity (eg, reduced brain volume and cortical thickness), were associated with slow gait measured at age 45 years. Lifelong compromised brain health—including poor neurocognitive functioning as early as age 3 years and childhood-to-adulthood decline in cognitive functioning—was associated with slower gait at midlife.
Gait speed at midlife may be a summary index of lifelong aging with possible origins in childhood central nervous system deficits.
Gait speed is a well-known indicator of risk of functional decline and mortality in older adults, but little is known about the factors associated with gait speed earlier in life.
To test the hypothesis that slow gait speed reflects accelerated biological aging at midlife, as well as poor neurocognitive functioning in childhood and cognitive decline from childhood to midlife.
Design, Setting, and Participants
This cohort study uses data from the Dunedin Multidisciplinary Health and Development Study, a population-based study of a representative 1972 to 1973 birth cohort in New Zealand that observed participants to age 45 years (until April 2019). Data analysis was performed from April to June 2019.
Childhood neurocognitive functions and accelerated aging, brain structure, and concurrent physical and cognitive functions in adulthood.
Main Outcomes and Measures
Gait speed at age 45 years, measured under 3 walking conditions: usual, dual task, and maximum gait speeds.
Of the 1037 original participants (91% of eligible births; 535 [51.6%] male), 997 were alive at age 45 years, of whom 904 (90.7%) had gait speed measured (455 [50.3%] male; 93% white). The mean (SD) gait speeds were 1.30 (0.17) m/s for usual gait, 1.16 (0.23) m/s for dual task gait, and 1.99 (0.29) m/s for maximum gait. Adults with more physical limitations (standardized regression coefficient [β], −0.27; 95% CI, −0.34 to −0.21; P < .001), poorer physical functions (ie, weak grip strength [β, 0.36; 95% CI, 0.25 to 0.46], poor balance [β, 0.28; 95% CI, 0.21 to 0.34], poor visual-motor coordination [β, 0.24; 95% CI, 0.17 to 0.30], and poor performance on the chair-stand [β, 0.34; 95% CI, 0.27 to 0.40] or 2-minute step tests [β, 0.33; 95% CI, 0.27 to 0.39]; all P < .001), accelerated biological aging across multiple organ systems (β, −0.33; 95% CI, −0.40 to −0.27; P < .001), older facial appearance (β, −0.25; 95% CI, −0.31 to −0.18; P < .001), smaller brain volume (β, 0.15; 95% CI, 0.06 to 0.23; P < .001), more cortical thinning (β, 0.09; 95% CI, 0.02 to 0.16; P = .01), smaller cortical surface area (β, 0.13; 95% CI, 0.04 to 0.21; P = .003), and more white matter hyperintensities (β, −0.09; 95% CI, −0.15 to −0.02; P = .01) had slower gait speed. Participants with lower IQ in midlife (β, 0.38; 95% CI, 0.32 to 0.44; P < .001) and participants who exhibited cognitive decline from childhood to adulthood (β, 0.10; 95% CI, 0.04 to 0.17; P < .001) had slower gait at age 45 years. Those with poor neurocognitive functioning as early as age 3 years had slower gait in midlife (β, 0.26; 95% CI, 0.20 to 0.32; P < .001).
Conclusions and Relevance
Adults’ gait speed is associated with more than geriatric functional status; it is also associated with midlife aging and lifelong brain health.